from The Hutchinson Unabridged Encyclopedia with Atlas and Weather Guide

English derivatives trader, who was responsible for the collapse in 1995 of London's oldest merchant bank, Baring Brothers, which was subsequently bought by Dutch group ING for a nominal fee of one pound sterling. The novel he wrote while imprisoned in Singapore, Rogue Trader, was made into a film in 1999, starring Scottish actor Ewan McGregor as Leeson. He subsequently studied for a degree in psychology, and advises companies on risk management and undertakes speaking engagements on his life experiences. In 2005 he released a new book titled Back from the Brink, Coping with Stress.

Leeson joined Baring Securities in 1989 and began trading in Singapore in 1992. He began making unauthorized trades, covering his losses in a secret account. In 1995 the markets collapsed and Leeson's actions were discovered. He was released from prison in 1999.

Born in Watford, England, the son of a plasterer, Leeson left school with few qualifications. He worked for Coutts and then Morgan Stanley, settling futures and options in Japan before joining Baring Securities. Posted to Singapore, he obtained a licence to trade in the Singapore International Monetary Exchange (SIMEX).

He became Baring's star Asian trader, making so much money that Baring's left him entirely in control of both front and back offices (trading and settlement) without knowing he had set up a secret error account (numbered 88888, initially to cover a colleague's mistake) to conceal the huge losses he made from unauthorized trading – the trades were so heavy that he actually moved Japan's Nikkei futures market. When the Kobe earthquake in Japan sent the markets crashing in 1995, Baring's was left in a situation it could not finance.

Leeson and his wife, Lisa (who later divorced him), fled to Malaysia, leaving Baring's bankrupt with debts of £860 million. He was arrested at Frankfurt airport, Germany, in March and extradited to Singapore, where he served three years of a six-year prison sentence for fraud. He was released early having been diagnosed with cancer.